Thermostat.



H. Y. NORWOOD. THERMOSTAT.

APPLICATION FILED NOV.29,1909.

986,023. Patented M317, 1911.

UNITED STATES PATENT OFFICE.

HARRY Y. NORWOOD, OF ROCHESTER, NEW YORK, ASSIGNOR TO TAYLOR INSTRUMENTCOMPANIES, OF ROCHESTER, YORK, A CORPORATION OF NEW YORK.

THERMOSTAT.

Specification of Letters Patent.

Patented Mar. '7, 1911.

Application filed November 29, 1909. Serial No. 530,412.

To all 'wlwm it may concern:

Be it known that I, HARRY Y. Nonwoon, of Rochester, in the county ofMonroe and State of New York, have invented certain new and usefulImprovements in Thermostats; and I do hereby declare the following .tobe a full, clear, and exact description of the same, reference being hadto the accompanying drawings, forming a part of this specification, andto the reference-numerals marked thereon.

The present invention relates to thermostats of the typeinwhich one ormore contacts are arranged to be engaged by an expansible conductingbody such as mercury in order to establish an electrical circuit ofwhich the expansible body forms a part, and the object of this inventionis l9 provide for securing the contacts to the casing contain- .ing theexpansible body in 'such a manner that greater life to the instrument isinsured.

To these and other ends theinvention relates to certain improvements andcombinations of parts all as will be hereinafter more fully described,the novel features being pointed out in the claims at the end of thespecification.

In the drawings: Figure 1 is a view showing the instrument and the meanssupporting the same; Fig. 2 is a detail and enlarged sectional view ofthe instrument, and Fig. 3 is a section on the line (z-a of Fig. 1.

An electric contacting thermostat is usually a regular mercury and glassthermometer having platinum wires fused into the glass with one end ofeach wire rojecting into the bore and into the path of the mercury tocomplete the electric circuit while the other end projects from theexterior of the stem and has a suitable conductor secured thereto. Theseplatinum wires at the point where they enter the glass are very brittleand are easily broken, thus requiring the exercise of great care inhandling them both during" the process of manufacturing as well as inuse, for once they are broken they cannot be repaired, and an instrumentthereafter has no.utility for the purpose, for

which it was designed.

In this invention a suitable casing 1, preferably made of glass, with abulb and a bored stem-as in an ordinary thermometer, has fused thereinone or more conductors 2,

' end embedded therein.

preferably in the form of platinum wires extending transversely throughthe stem of the casing, and each projecting at its inner end into thebore 3 thereof and at its outer end from the outer surface of the stem.

At the outer end of each conductor wire is electrically connected anenlarged contact 4 which preferably is in the form of a copper sleevesurrounding the stem in proximity to the conductor 2, and having thewire In order that this contact will lie in most intimate engagementwith the glass and the conductor 2, the contact is preferably depositedthereon electrolytically in accordance with any electroband of copperand this band cannot be shifted without breaking the glass so that theplatinum wire cannot break away where it enters the glass. The thin filmof silver or other material deposited by chemical action is in the mostintimate contact possible with the surface of the glass, conforms to themost minute inequalities in its surface, and is with difliculty strippedfrom it, and the copper bandwhen deposited by electrolysis thereon formsa solid contact which is practically iridestructible- Every part of theband may serve as apoint of contact so that the conductor wire may beeasily connected thereto in order to complete a circuit.

As a simple means for supporting the there may be rovided sleeves 6 eachhaving a. stem 7 pro ecting therefrom and passing ,through an insulatingbushing 8 in a suitable'wall -or support 9', said stem being secured inthe bushings in any suitable manner as, by anut 10, and the circuitwires 11 being'held in engagement with the nuts 10 bynuts 12 alsofitting on the stems 7. Two or more of the supporting sleeves 6 areaxially aline'd and the thermostat stem is fitted into them so that itscontacts 4 lie within the sleeves 6. In this position, the screws 13 orother suitable devices maybe caused to frictionally engage the contacts4 to maintain the thermometer against movement in the sleeve.

A thermostat constructed in accordance with this invention has theconductors or platinum wires supported in such a manner that thebreaking thereof is prevented and thus the life of the thermostat isgreatly increased. lhe size of the thermostat contacts are also greatlyincreased thus permitting a quicker connection of the instrument to thesignaling circuit.

I claim as my invention:

1. An electrical alarm thermostat embodying a stem of insulatingmaterial having a bore therein, an expansible conductor in the bore, astationary conductor extending through the Wall of the stem into thebore, and a contact plate or body on the exterior of the stem,consisting of metal deposited upon the stem by electrolysis and havingthe outer end of the stationary contact embedded therein.

9.. An electrical alarm thermostat embodying a tubular stem ofinsulating material having a bore therein, an expansib e conductor inthe bore, a stationary conductor extending through the Wall of the steminto the bore, and an annular contact plate or body encircling the stemconsisting of metal HARRY Y. NORWOOD.

\Vitnesses VVALTER B. PAYNE, HENRY W. HALL.

